Metal ion-assisted assembly of one-dimensional polyrotaxanes incorporating cucurbit[6]uril

Three cucurbit6]uril (CB6])-based polyrotaxanes Cu(H₂ C6N4)(CB6])]Cl₄·12H₂O (1), Co(H₂ C6N4)(CB6])]Cl₄·14H₂O (2) and Ag(C6N4)(CB6])]NO₃·7H₂O (3) are prepared using N,N′-bis(4-pyridylmethyl)-1,6-hexanediamine (C6N4) threading into CB6]'s and metal ions' assistance. Single-crystal X-ray diffraction analyses reveal that polyrotaxanes 1, 2 and 3 all have 1D chain structure where 1 and 2 are linear and 3 has two shapes, linear and sawtooth, respectively. The effects of guest molecules, metal and counter ions as well as intermolecular weak interactions on the architectures of polyrotaxanes are discussed.